In such architecture, the server encodes, that is, compresses, what it broadcasts before sending it to the client terminal. If the server had to display on an own screen the images it broadcasts, their compression would not be necessary. To perform compressing, the server carries out a capture of its own display, codes it and sends it through the network to the client terminal. Each image to be displayed is stored in a buffer, known as framebuffer, of the server and is generally coded in an RGB format (“Red Green Blue”) which constitutes the most direct manner to encode the images, the three plans corresponding to the three elementary colors red, green and blue. Then, the image is generally transformed in a YUV format (or luminance-chrominance). The first plan, called luminance plan (Y) represents the luminous intensity of the pixels. The two following plans correspond to the chrominance (U, V) and carry the color information. There mainly exist two YUV formats:                format 4:2:0 (also known as YUV12) for which both chrominance plans each contain one a sample per four pixels,        format 4:4:4 for which the three plans have the same size (i.e. there is a chrominance sample per pixel).        
The encoding carried out by the server is a space-time type encoding such as a H264 encoding. The H264 standard is a video coding standard jointly developed by the VCEG (“Video Coding Experts Group”) and the MPEG (“Moving Pictures Experts Group”). This standard makes it possible to encode video streams with a speed lower than twice less that obtained by the MPEG2 standard for the same quality. A space-time encoding encodes integrally only a portion of the images to be transmitted in order to reconstitute a video. The H264 standard includes the types of image known and defined in the MPEG2 standard, namely:                I images (Intra), the coding of which does not depend on any other image,        P images (Predictive), the coding of which depends on previously received images,        B images (Bi-predictive), which depend on previously and/or subsequently received images.        
However, the implementation of such an encoding solution raises a number of difficulties when it comes to the real time transfer of the server display on the client terminal.
Thus, such a coding mode is very much consuming in terms of time and of computation means. To save band-width, the data must be compressed as much as possible. This important compression imposes a great complexity in terms of encoding. Thus, the server must not only carry out image compression but also carry out several computations to determine the addresses and the data to be encoded. This energy overconsumption makes the implementation of other applications running on the same server delicate.